CHICAGO – Advocates of gay marriage in Illinois celebrated landmark rulings from the U.S. Supreme Court on Wednesday, saying the clarity on a federal marriage act and California ban would benefit same-sex Illinois couples married in other states and fuel momentum to legalize gay marriage in President Barack Obama’s home state.

The high court struck down a key provision of the federal Defense of Marriage Act, meaning that legally married same-sex couples should get the same federal benefits as heterosexual couples. In a separate, narrower decision, the court also paved the way for same-sex marriage in California by holding that defenders of California’s gay marriage ban didn’t have the right to appeal rulings that struck down the ban.

The DOMA ruling is expected to affect numerous same-sex couples who were legally married in other states and live in Illinois, a number that’s not officially tracked but advocates estimate is in the thousands.

“I am thrilled beyond belief,” said Courtney Reid, a 51-year-old Illinois resident who married her longtime partner last year in New York. “It certainly means a lot for my wife and me.”

The benefits include filing joint taxes, receiving breaks on estate taxes and receiving Social Security survivor benefits. But there were still lingering questions about the ruling’s full impact on married couples living in Illinois. For example, immigration law focuses on where people married, but eligibility for survivor benefits essentially depends on where a married couple is at the time of a death.

Obama directed the Justice Department Wednesday to work with other executive branch agencies to begin implementing the court’s decision, so more guidance for states like Illinois may follow. The Illinois Attorney General’s office is reviewing the decision for its impact on Illinois, according to a spokeswoman.

A couple that is legally married in another state and resides in Illinois is recognized as a civil union in the state, even if the couple hasn’t applied for one. The number of couples in civil unions in Illinois — who may or may not be legally married elsewhere — is roughly 5,300.

While advocates of gay marriage praised the decision on DOMA, several also said it was “bittersweet.” Illinois allowed civil unions in 2011 but hasn’t legalized gay marriage, despite a push from Obama, Gov. Pat Quinn, Chicago Mayor Rahm Emanuel and lobbying from well-organized gay rights groups.

“It just underscores the fight for the freedom to marry,” said Bernard Cherkasov, the CEO of Equality Illinois. “We’re going to take that message to the lawmakers in our districts.”

Efforts to legalize gay marriage in Illinois were halted earlier this year when lawmakers decided not to call the matter for a vote. The sponsor of the measure, Democratic Rep. Greg Harris, said he simply didn’t have the votes needed in the Illinois House and wanted to give his colleagues more time to think it over in their home districts.

The move received some criticism from Chicago’s active gay rights lobby, which has made an intense push since last year. There was also short-lived talk of barring politicians from the city’s annual Pride Parade, scheduled for this weekend. The festive event attracts hundreds of thousands of people each year including elected officials and those running for office.

Harris said the court’s decision on Wednesday would only help, and a same-sex marriage bill would be revived in the fall session.

“Illinois must step up and join our brother and sister states,” Harris said. “It’s now more important than ever.”

But opponents of same-sex marriage said they would continue to fight efforts in Illinois. Earlier this year, several black megachurches were part of intense efforts to fight legislation in Springfield and launched aggressive robo-call campaigns.

One group, the African American Clergy Coalition, vowed to continue, saying that marriage is between one man and one woman.

“The people of the state of Illinois, along with 38 other states, still have the right to determine if gay marriage should become law in their respective states,” the group said in a statement.

Some opponents of same-sex marriage said that while the decision would likely help the movement for same-sex marriage, there was still a lack of clarity when it came to benefits for married couples in Illinois.

“It creates an interesting question, are you entitled to that benefit or not?” said Paul Linton, special counsel to Thomas More Society, a public interest law firm that opposes gay marriage. Still, he added that the decision “probably gives the proponents of same-sex marriage more political ammunition.”

Among those eagerly awaiting the rulings were Jason Orne, 27, and Austin Duus, 26, who read the court’s decisions on their laptops at Chicago’s gay community center, the Center on Halsted. A television in the lobby was tuned to C-SPAN.

The couple lives together in Chicago and said the decision puts extra pressure on state lawmakers in Illinois to approve same-sex marriage.

“Change is only a matter of time,” said Orne, a graduate student.

Efforts to legalize gay marriage in Illinois are also ongoing in the courts. Last year a lawsuit was filed by the American Civil Liberties Union and New York-based Lambda Legal, which represents 25 couples who were denied marriage licenses in Cook County. The suit also challenges a state law that defines marriage as between a man and woman.

While the decision on the federal case doesn’t have an impact on the state law, it’s expected to help the lawsuit’s chances, said Camilla Taylor, marriage project director for Lambda Legal in Illinois. In a statement, Attorney General Lisa Madigan, who supports gay marriage, agreed.

“It’s doomsday for DOMA,” Taylor said. “It’s extremely helpful. There’s some wonderful language about how important it is to marry. Their dignity, their liberty, their equality. That will be extremely helpful in court.”